Aerial fireworks products, such as skyrockets, bombs and the like have been known for centuries. Bombs, or mortars, typically are launched from upright launch tubes by detonation of a concussion charge or other propulsion means. Once the bomb reaches its desired elevation (determined by an internal fuse or other means), the bomb explodes and disperses a plurality of stars stored within the body of the bomb. These stars, which are formed from a pyrotechnic composition that bums with a characteristic color, depending on the chemical formulation of the pyrotechnic composition, ignite and are dispersed in the atmosphere to form a firework pattern.
Firework patterns produced by bombs are typically spherically symmetric, but can also have other geometries. Planar shapes, including circles, as well as asymmetric shapes, can be produced by various means. For example, U.S. Pat. No. 6,324,981 discloses a pyrotechnic projectile including a body which contains a bursting charge and a combustible charge. The combustible charge is dispersed within the bursting charge in a pattern that corresponds to the shape of the firework pattern that is to be obtained in the sky.
Known pyrotechnic projectiles, however, are limited in the precision with which the firework pattern obtained in the sky can be controlled. Moreover, known projectiles are constrained to produce a single firework pattern, which is controlled by the disposition pattern of the stars or other combustible materials within the both of the projectiles.
Furthermore, known pyrotechnic projectiles do not afford control of the firework pattern subsequent to ignition of the stars. That is, once the stars ignite, they follow a generally ballistic flight path from their respective points of ignition.
A need exists for a pyrotechnic projectile which affords precise control of a firework pattern obtained in the sky by use of the projectile. In particular, a need exists for a pyrotechnic projectile that can be programmed to produce a variety of firework patterns, whether symmetric or asymmetric, without the need for changing the disposition of stars or other combustible materials within the body of the projectile.
A need also exists for a pyrotechnic projectile that enables production of an animated firework pattern, that is, a firework pattern that changes in a controlled way even after ignition commences.
A need also exists for a method of producing firework patterns using such improved pyrotechnic projectiles.